Spring Effect and Dynamic Properties
| The design, material and/or construction of, or any treatment to, the clubhead (which includes the club face) must not:
(i) have the effect of a spring which exceeds the limit set forth in the Pendulum Test Protocol on file with The R&A; or
(ii) incorporate features or technology including, but not limited to, separate springs or spring features, that have the intent of, or the effect of, unduly influencing the clubhead’s spring effect; or
(iii) unduly influence the movement of the ball.
Note: (i) above does not apply to putters.
The new Rule limiting "spring effect" was introduced on 1 January 2008 and it applies to all golfers of all abilities and in all forms of play. Whilst the Rule applies to all clubs except putter, its focus is mainly on driving clubs.
Given that this is purely a performance related limit which cannot be measured easily in the field without specialised equipment and cannot be assessed through a visual inspection of the clubhead, The R&A has compiled and maintains a List of Conforming Driver Heads. This List can be accessed via The R&A’s website (www.randa.org) and it is updated weekly.
For competitions restricted to highly skilled players, a Condition of Competition may be introduced requiring players to use a club which is included on this List. This Condition is an additional requirement for these players, which means that, not only must their clubs conform to the Rules, but the model and loft must also be included on the List of Conforming Driver Heads. This Condition, or additional requirement, is not recommended for use at Club level golf and this is sometimes mistakenly interpreted to mean that the Rule does not apply to Club level golfers. However, for the avoidance of doubt, the position is that the drivers used by Club level golfers must still conform to the Rules, but they do not necessarily have to be on the Conforming List. Most importantly, they must not be included on the List of Non-conforming Driver Heads.
Full details of the Driving Club Condition can be found in Appendix I of the Rules of Golf.
As well as meeting the requirements of clause (i) in the above Rule, clubs are also tested for compliance to clause (ii) using the Pendulum at points on the face other than at the centre and, depending on the results, other tests may be carried out. Any club which is found to include a feature that is designed to act like a spring, independent of the level of flexibility achieved by the design, could be ruled non-conforming.
If claims of "spring like" qualities are made by the manufacturer which suggest that a club is manufactured to be in excess of the limit, or there is evidence to suggest that the club is indeed over the limit, then the club would be deemed to be non-conforming.